As medical techniques, biologic materials and pharmaceutical preparations have become more sophisticated, numerous problems inherent in their being shipped arises. One such problem area relates to the shipment and preservation of human tissue or human organs and more specifically human skin. When attempting to transport living tissue and specifically human skin, the contents of the shipment must be maintained within a narrow temperature range, which is preferably from about 92.degree. F. to 104.degree. F. Notwithstanding the restrictive temperature window, there are many problems inherent in shipping human skin. Human skin is a fragile structure, being labile to vibratory and mechanical damage. Shipping or transporting human skin, also requires that the skin specimen itself resides submerged in a liquid, nutrient-rich broth. In this condition the tissue sample continues to feed and maintain its viability. Failure to maintain the temperature range without exception results in loss of the tissue sample. For the burn patient or any patient undergoing a skin-graft operation, the patient may lose his/her opportunity for undergoing a life-saving procedure.
Therefore, there has been a recognized longstanding need for furnishing a temperature-controlled container for shipping human tissue. The container must enable the manufacturer, shipper, warehouseman and end-user to ensure the safe delivery of the skin or tissue product. From industry experience, it has been further recognized that human tissue materials retained within such a container must not only be maintained at very specific temperatures but also free from shock and vibration. It should be noted that the prior art presents a multitude of cryogenically maintained transport and storage containers.
The prior art presents a diverse array of temperature-maintained containers. Containers in accordance with the prior art run the gamut from what amounts to an insulated pizza delivery box, on the one hand, to a sophisticated temperature-controlled container the size of a "steamer" trunk on the other. Obviously, such designs fall outside of dimensional and weight parameters necessary for shipping through accepted channels. Overnight and courier delivery services are not readily equipped to deliver oversized containers or containers that require special power needs.
The main problem heretofore remaining unsolved, appertains to a container that maintains a desired temperature range while remaining maneuverable, low in cost, dimensionally acceptable to transport and later storage, and without the need for supervision or intervention during shipping. The desired container must be temperature controllable and provide a specific interior temperature for a prescribed number of hours. Being temperature-controlled is one quality, but being shock resistant is essential.
Given the facility that the medical profession has for being able to utilize human tissues and organs, it is now desirable to increase the amount of time between, transport, storage and use of the biologic materials. Therefore, it is highly desirable to provide a temperature-controlled container that will allow the user to store, transport and ultimately use the material over a period of time which can be measured in terms of days as opposed to minutes and hours. Thus, the need for intricate hand delivery and human failure is minimized by allowing for the tissue to be shipped over longer distances and time periods.
U.S. Pat. No. 4,723,974 issued to Ammerman discloses a container for transporting an amputated extremity by utilizing a flexible walled inner container mounted inside of a flexible walled outer container. The space within the outer and inner walls of the outer and inner containers is filled with a chemical that, when activated, causes a significant reduction in temperature of the environment located within the inner container. The amputated part is maintained in a saline solution and covers the same. It is disclosed that the amputated sample appendage is to be maintained at a sub-ambient temperature.
U.S. Pat. No. 5,040,678 issued to Lenmark discloses a container for transporting biologicals where there is essentially a box within a box construction. A block adds to the shock absorbing qualities.
U.S. Pat. No. 4,145,895 issued to Hjerstraud et al discloses a box within a box design wherein a coolant material like deuterium oxide, undecyl cyanide, 4-bromo-decanoic acid and 2 bromo-decanoic acid is used to maintain the contents in a sub-ambient or cold condition.
U.S. Pat. No. 4,630,448 issued to Blistad discloses a wide-mouthed flexible, collapsible, sterile bag made of sheeting of poly(ethylene vinyl acetate) for storing and shipping solid living tissue at very low temperatures. The thrust of the disclosure resides in maintaining the sterile bag flexible and intact at cryogenic temperatures.
U.S. Pat. No. 4,530,816 issued to Hamilton discloses a method and device for shipping biologic materials within a preferred temperature range of from 4.degree. C. to 10.degree. C., that is near but above freezing. The sample must not be exposed to a temperature of less than 0.degree. C. An isothermal cup or Dewars Flask retains the sample and gelatinized ice retained in a metal container provides the cooling media.
U.S. Pat. No. 4,502,295 issued to Pereyra discloses a storage unit for maintaining organs in a hypothermic environment, within a temperature range of from 0.degree. C. to 7.degree. C., by utilizing a series of containers within containers. The most important feature is the sub-ambient condition within which the sample is maintained. An inner container provides a receptacle for ice thereby maintaining a cold environment
U.S. Pat. No. 4,958,506 issued to Gulham discloses a container for transporting grafts wherein a constant temperature equal to +4.degree. C. is maintained for 10 hours given an ambient temperature which is "normal." The system uses a thermal exchanger that is charged with a gas like butane.
U.S. Pat. No. 4,986,076 issued to Kirk et al discloses the method of using an endothermic salt to maintain low temperature environment.
Notwithstanding the foregoing art that teaches low temperature maintenance, there is a recognized longstanding need for a container to transport biological materials at elevated temperatures. It should be noted that a container capable of such super-ambient parameters, while also being shock resistant and amenable to shipping through normal shipping channels is not described in the art. In addition, while various forms of container-heaters have been tried, there has been no effective means of using a heater to provide continuous interior container temperatures within a few degrees of tolerance while maintaining physical and cost parameters.
Therefore, the principal object of the present is to provide a temperature controlled container for transporting human tissue at a specific temperature range.
Another object of the present invention is to provide a temperature controlled container where the interior temperature may be maintained at a super ambient level of from 60.degree. F. to 110.degree. F. for at least 120 hours.
A further object of the present invention is to employ a sensitive heating, and thermostat means to influence the interior container temperature to thereby maintain a constant inner temperature at a desired temperature within four degrees from a set temperature.
Yet another object of the present invention is to provide an insulated temperature-controlled container capable of retaining a fragile sample and frangible container in an undamaged condition.
Another object of the present invention is to provide a heating means to modify and maintain interior container temperature in a less cold condition.
The instant invention provides a container adapted to retain a biologic sample like human tissue, and more specifically human skin at a desired temperature range of from 92.degree. F. to 104.degree. F. for a period of at least 120 hours. To implement this end, an outer insulated container is provided with upstanding insulated walls, an insulated base and an insulated lid which nest by means of a friction plug and T-joint within the uppermost boundary of the annular chamber created by the upstanding wall and base. A power source is disposed within a recessed power source retention area. From the power source, and through leads the power is transmitted to a thermostat means and to a heating means. The heating means is in intimate communication with an interior sample container. ** above the sample container resides a eutectic pack to assist in maintaining the sample at an elevated or critical temperature.
The heating means is preferably in communication with the inner sample container, operates on a low voltage power source sufficient to activate a heating means and is thermostatically controlled so that a specific temperature range (92.degree. F. to 104.degree. F.) is maintained. An outer container is adapted to receive the inner sample container, the outer container being adapted to provide excellent insulation from outside temperatures and prevent mechanical damage to the interior sample container.
The present invention provides an outer insulated container with an insulated wall and insulated bottom creating an inner annular chamber. An insulated lid means interlocks and reversibly seals the outer container. In the annular chamber created as the inner area of the outer container an area is provided to retain a power source. The power source is in communication with, and supplies a thermostat means and a heating means. The heating means is preferredly further comprised of a heating means, the heating means being retained in a matrix to present the same in a radial array and is reversibly affixed to an inner container which retains the skin sample. The heating means is actuated by an on/off switch or by completing the connection with the power source. When activated the heating element provides warmth to the inner container which retains the biologic or skin sample and to the inner annular chamber. A series of isolating shock absorbing means may be in communication with at least the four comers of a common shipping corrugated container and the corresponding comers of the outer container.
The thermostat which may be a microchip, solid state device or mechanical means provides power and therefore heat when it senses that the sample or the surrounding ambient temperature falls below pre-determined levels. The thermostat and heating means provide the user with the ability to maintain super and sub-ambient temperatures and may be used to make chamber temperature less cold or more warm depending on the desired temperature range.